IgG Subclass Deficiency Research Articles

Atopy, immunological changes, and respiratory function in bronchiectasis.

Cystic fibrosis has been reported to be associated with an increased prevalence of atopy and reversible airways obstruction. To determine whether such features can also result from other chronic suppurative lung infections, we studied 23 patients with proved bronchiectasis, and 23 age and sex matched normal controls. A personal or family history of atopy was reported with equal frequency in the two groups. Although the groups displayed a similar prevalence of positive immediate hypersensitivity skinprick test responses, the positive patients reacted to more antigens (p less than 0.05) and had larger weal diameters (p less than 0.01) than the positive controls. Other indices, such as blood eosinophil counts and serum IgE, did not differ significantly. Serum concentrations of immunoglobulins G, A, and M and of the four IgG subclasses tended to be higher in patients than controls, but only in the case of IgA (p less than 0.01) was this difference significant. No case of IgG subclass deficiency was noted. The patients displayed significant airflow obstruction, the mean basal one second forced expiratory volume (FEV1), forced vital capacity (FVC), and peak expiratory flow rate (PEFR) being 67%, 77%, and 67% of their predicted values. There was evidence of a significant reversible obstructive component in that FEV1 or PEFR or both increased by 15% or more in nine of the 23 patients after inhalation of fenoterol, the mean increases in FEV1, FVC, and PEFR for the whole group being 9.5%, 11%, and 16.9%. These results indicate that while bronchiectasis provokes a hyperimmune response it differs from cystic fibrosis in that there is no significant increase in the prevalence of atopy. The finding of reversible airways obstruction, however, suggests that bronchodilators may be useful adjuncts to treatment.

The serum igg subclass levels in healthy infants of 13–62 weeks of age

The levels of IgG1, IgG2, IgG3, and IgG4 were determined in serum samples of 160 infants aged 13–62 weeks, and of their mothers. In addition the serum IgM, IgG, IgA, and IgD levels of the infants are presented. The results show that IgM, IgG1, and IgG3 slightly increase during the first year of life, whereas IgG2, IgG4, IgA, and IgD hardly do. This difference in the development of the various immunoglobulin isotypes reflects differences in the terminal maturation of subsets of B-lymphocytes into plasma cells. About 50% of the infants of this age had no detectable IgG4 and three children had no IgG2. These observations indicate that longitudinal investigations are needed in children suspected of a IgG2 or IgG4 subclass deficiency. No statistically significant influence of sex on the IgG subclasses could be demonstrated in these infants.